Brigonius snorted. 'The Romans count us so they can tax us. The farmers only grow more wheat to meet the demands of the soldiers who push us around. And then they have to pay tax on the coin they earn.'

'Yes,' Severa said, a touch impatiently, 'but that's the point. You have to see all of this as a great wheel, Brigonius-like the waterwheel of the mill over there. Once the farmers grew only for themselves. Now they grow a surplus, which they take to the towns to sell. The taxes they pay on their profits are used to develop the towns and to pay the soldiers, who, hungry, must be fed by the farmers' surplus…Around and around it goes, a wheel driven by a river of money. And everybody benefits, everybody grows prosperous, and everybody is at peace. Why, there have probably never been more people alive in Britain than today. What's wrong with that?'

'But what's the point of it all? The mill-wheel grinds flour for bread. What purpose does your money-wheel serve?'

'Why, it grinds up people. It smashes up petty tribes like your own and bakes the fragments into an empire.'

'It makes everybody the same,' Brigonius said resentfully.

'Yes! And that is the power of it.' Severa dug into her purse and produced a coin, stamped with Hadrian's head. 'Look at this, Brigonius. You could travel along roads just like this one from Britain to Asia, and everywhere you could ask for your daily bread in Latin, and pay for it with this coin. A single language, a single currency, right across a continent. And Britain is part of it! Don't be sentimental, Brigonius! Open your eyes and see the shining future-and embrace it.'

As she made this little speech she touched his hand. Her grip was strong, her flesh oddly cold. Looking at her pale eyes he saw her ambition, and he wondered uneasily just how unsentimental she would prove to be in pursuing her goals.

In the back of the carriage, Lepidina puzzled out a fresh bit of wordplay in Ovid's poetry and laughed softly, her voice light as a bird's.

V

Unlike most other British towns Londinium had not been founded on the site of an older settlement. When Claudius came this way there had been nothing at all, Severa said, nothing but the mud huts of a few fisher-folk. Now along the shining river barges and sea-going ships cruised purposefully, and docks sprawled along both north and south banks of the river, with cranes rising like gaunt birds. Beyond a hinterland of warehouses and granaries there were signs of still more impressive buildings under construction.

Using her sketchy map Severa showed him why Londinium had risen. 'You see, the river is tidal, all the way to this point, and navigable much further inland. And the city itself is a node of road systems that arrow off across the island north, west, east and south. It is a natural port for trade with Gaul and further afield…'

It was a port for an imperial province, Brigonius saw, a port for continental trade. Britain did not need Londinium; Britannia did.

After a final overnight stop they approached Camulodunum. It was early in the morning. As they neared the town the road, growing busier, was lined with tombstones, urns half-buried in the ground. Severa told Brigonius that the Romans didn't allow burials within a town's boundary, so cemeteries grew up on the major routes out of town.

The wall of Camulodunum itself became visible, a dark line cutting across rising ground. For miles around the wall, however, Brigonius made out roundhouses, barns and earthworks, most of them abandoned. The Roman town seemed to have been planted on a low hill, overlooking what had once been a much more extensive settlement, now disappearing under the plough.

Outside the town they glimpsed a vast walled structure of bright new stone, too small to be a town, the wrong shape to be a fort. It turned out to be an arena where chariot races were run, under the auspices of priests from the town's temple. Brigonius was amazed at the extravagance. But the arena's upkeep was paid for by the betting on the races, and the eyes of Severa, an instinctive gambler, lit up at the thought.

Severa sent a slave running ahead to prepare for their arrival. As a result they were met on the road by one Flavius Karus, whom Severa introduced as a lawyer with whom she had corresponded over the business of Hadrian's frontier works.

Brigonius and Karus eyed each other suspiciously. Karus was a tall man, as tall as Brigonius, but his belly was heavy and rippled like a sack of water when he walked. His hair was as dark as Brigonius's, though peppered with grey, and he was clean-shaven where Brigonius was bearded. He had donned a toga for the occasion, albeit a bit grubby and splashed with mud at its hem, but he was clearly every bit as British as Brigonius.

Not only that, Brigonius thought, Karus paid rather too much attention to Lepidina. 'So this is the delightful daughter whose company you promised in your letters!'

Lepidina was used to male attention, welcome and unwelcome. But Brigonius thought he saw a gleam of calculation in Severa's eye. He wondered if she used her daughter's charms as a lure to snare fat old fools like Karus as well as youngsters like himself.

The four of them were to walk to Karus's home, inside the walled town; the slaves would follow with the luggage. Karus led the way along the crowded road. The town wall loomed over them: twelve feet high, Karus said with mock pride, not counting the parapets, and eight feet thick. The road passed through an immense double gate. Karus said this had once been a triumphal arch, built to celebrate Claudius's visit here. After Boudicca's disastrous uprising it had been built into the town's stout new walls.

Under the gate Brigonius was stopped by a patrol of soldiers who roughly searched his clothing. The Romans had a law that you couldn't carry a weapon inside any town, and they enforced it, especially where Brittani were concerned. Brigonius submitted; he was used to it. The women watched this little exchange, Severa with a jackdaw's fascinated stare, Lepidina rather bewildered. Brigonius imagined they had never seen people of their acquaintance treated this way.

Inside the town narrow streets divided the city into blocks of housing Karus called insulae, islands. Every surface was covered with slogans and sketches. To Brigonius the town was cramped and crowded, all straight lines and square angles and a jumble of distracting imagery. It was strange to think that somewhere under all this painted stone and plaster Cunobelin had once held court at the heart of his own empire, a capital now erased from the earth.

Karus's home was in a side-street. It was a tall, skinny sort of building on a square base, its plastered walls gleaming white, roofed by red tiles. At street level the doors were flung wide to reveal a shop, with a broad counter set out with food: meat, pastries, bits of fruit. Still early in the morning, customers crowded the counter, buying their breakfast. The smell of cooked meat made Brigonius's mouth water, but he wondered why all these folk had not simply eaten at home.

Karus led his guests through the shop and to a staircase at the back. It turned out that Karus owned the space on top of the shop, which was, to Brigonius's surprise, like a second house piled up on top of the first. The space up here, small to begin with, was sliced up into smaller rooms by inner partitions. Karus went around lighting wall-mounted oil lamps and candles. The rooms had tiny windows with panes of bluish glass, but it was dark inside the apartment, even on so bright a morning, for the building was in the shadow of others.

Severa and Lepidina made slight noises of appreciation as Karus showed them around. 'It isn't terribly large,' Karus said apologetically. 'But it's all a poor lawyer can afford. You wouldn't believe how expensive land has become close to the town centre.'